Joe's journey isn't just a personal challenge. It also draws attention to a serious public health crisis. Obesity is one of America's top-three killers.

More than one-third of American adults are obese, according to the Centers for Disease Control and Prevention. And just like our guts, those numbers are only getting bigger. Some health experts forecast that 42 percent of the U.S. population will be obese by 2030.

The obesity plague is also spreading to other countries.

Carrying a few extra pounds isn't necessarily a death sentence. But people who are grossly fat (a BMI of 30 or higher) run an increased risk for diabetes, heart attack, stroke, and certain types of cancer — all of which are completely preventable illnesses.

Obesity-related conditions also come at a dollar cost. Preventable diseases like diabetes and pre-diabetes will account for about 10 percent of total health care spending by 2020, at an annual cost of almost $500 billion.

Fruits and vegetables fill up your stomach and stop the craving for excess calories, the documentary claims.

The average American dinner plate is made up of 50 percent meat, 25 percent a white, refined carbohydrate and 25 percent vegetable. In this diet, Americans aren't getting enough nutrients to stop craving more food and excess calories.

But as he continued drinking — and shedding pounds — he felt better both physically and mentally.

Joe's favorite juice was the "Mean Green Juice," a mixture of kale, apples, lemon, cucumber, celery and ginger. However, it's important to vary your fruits and vegetables so that you're getting a range of colors — and therefore different nutrients — every day.

Most commercial juices are processed and lack the vitamins, minerals and phytonutrients found in freshly juiced fruits and vegetables. That's why it's important to consume only home-made juices.

And remember, a juice fast is an extreme form of dieting. It can be dangerous for pregnant women and anyone with diabetes or other medical issues. You should always consult a health professional before starting a juice fast longer than three days.

After 49 days, Joe had lost 67 pounds. His total cholesterol dropped from 204 to 135. (Doctors recommend total cholesterol levels below 200). His LDL cholesterol (that's the bad cholesterol that builds up on the walls of your arteries and can lead to heart attacks) went from 132 to 86.

His story inspired others, including a morbidly obese truck driver with the same rare condition, to go on a juice fast.

The cost of a conventional juice fast is $14 per day, according to the filmmaker. An organic juice fast runs around $28.50 per day. You should also factor in the cost of the juicer, which range in price from $100 to $400.

It may seem expensive, but can be well worth the cost. Six months after finishing the fast, Joe is 90 pounds lighter and off his prescription drugs. Though back on solid foods, he's altered his lifestyle to include more fruits and vegetables and exercise (it's not clear what Joe's fitness routine was during the 60-day fast).